fix: use environment configuration when creating a byte channel

src/main/java/software/amazon/nio/spi/s3/S3ReadAheadByteChannel.java

@@ -239,4 +239,12 @@ private CompletableFuture<ByteBuffer> computeFragmentFuture(int fragmentIndex) {
     Integer fragmentIndexForByteNumber(long byteNumber) {
         return Math.toIntExact(Math.floorDiv(byteNumber, (long) maxFragmentSize));
     }
+
+    public int getMaxFragmentSize() {
+        return maxFragmentSize;
+    }
+
+    public int getMaxNumberFragments() {
+        return maxNumberFragments;
+    }
 }

src/main/java/software/amazon/nio/spi/s3/S3SeekableByteChannel.java

@@ -21,7 +21,6 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import software.amazon.awssdk.services.s3.S3AsyncClient;
-import software.amazon.nio.spi.s3.config.S3NioSpiConfiguration;
 import software.amazon.nio.spi.s3.util.TimeOutUtils;
 
 class S3SeekableByteChannel implements SeekableByteChannel {
@@ -54,9 +53,7 @@ private S3SeekableByteChannel(S3Path s3Path, S3AsyncClient s3Client, long startA
             throw new IOException("The SYNC/DSYNC options is not supported");
         }
 
-        // later we will add a constructor that allows providing delegates for composition
-
-        var config = new S3NioSpiConfiguration();
+        var config = s3Path.getFileSystem().configuration();
         if (options.contains(StandardOpenOption.WRITE)) {
             LOGGER.debug("using S3WritableByteChannel as write delegate for path '{}'", s3Path.toUri());
             readDelegate = null;

src/test/java/software/amazon/nio/spi/s3/S3SeekableByteChannelTest.java

@@ -5,38 +5,46 @@
 
 package software.amazon.nio.spi.s3;
 
-import java.time.Instant;
-import org.mockito.Mock;
-import software.amazon.awssdk.core.ResponseBytes;
-import software.amazon.awssdk.core.async.AsyncRequestBody;
-import software.amazon.awssdk.core.async.AsyncResponseTransformer;
-import software.amazon.awssdk.services.s3.S3AsyncClient;
-import software.amazon.awssdk.services.s3.model.*;
+import static java.nio.file.StandardOpenOption.CREATE;
+import static java.nio.file.StandardOpenOption.READ;
+import static java.nio.file.StandardOpenOption.WRITE;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.lenient;
+import static org.mockito.Mockito.when;
+import static software.amazon.nio.spi.s3.S3Matchers.anyConsumer;
 
 import java.io.IOException;
 import java.net.URI;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.OpenOption;
+import java.time.Instant;
 import java.util.Collections;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import org.junit.jupiter.api.AfterEach;
-
-import static java.nio.file.StandardOpenOption.CREATE;
-import static java.nio.file.StandardOpenOption.READ;
-import static java.nio.file.StandardOpenOption.WRITE;
-import static org.junit.jupiter.api.Assertions.*;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
-
-import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.lenient;
-import static org.mockito.Mockito.when;
-import static software.amazon.nio.spi.s3.S3Matchers.anyConsumer;
-
+import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+import software.amazon.awssdk.core.ResponseBytes;
+import software.amazon.awssdk.core.async.AsyncRequestBody;
+import software.amazon.awssdk.core.async.AsyncResponseTransformer;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.model.GetObjectRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
+import software.amazon.awssdk.services.s3.model.HeadObjectRequest;
+import software.amazon.awssdk.services.s3.model.HeadObjectResponse;
+import software.amazon.awssdk.services.s3.model.NoSuchKeyException;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+import software.amazon.awssdk.services.s3.model.PutObjectResponse;
 
 @ExtendWith(MockitoExtension.class)
 @SuppressWarnings("unchecked")
@@ -149,4 +157,15 @@ private S3SeekableByteChannel seekableByteChannelForRead() throws IOException {
         return new S3SeekableByteChannel(path, mockClient, Collections.singleton(READ));
     }
 
+    // test that the S3SeekableByteChannel uses the buffer size from the configuration set for the FileSystem
+    @Test
+    public void testBufferSize() throws IOException {
+        fs.configuration().withMaxFragmentSize(10000);
+        fs.configuration().withMaxFragmentNumber(10);
+        try(var channel = (S3SeekableByteChannel) fs.provider().newByteChannel(path, Set.of(READ))) {
+            assertEquals(10000, ((S3ReadAheadByteChannel) channel.getReadDelegate()).getMaxFragmentSize());
+            assertEquals(10, ((S3ReadAheadByteChannel) channel.getReadDelegate()).getMaxNumberFragments());
+        }
+    }
+
 }